Power semiconductor device including a semiconductor layer based on silicon carbide

A power semiconductor device comprising:

• a semiconductor layer based on silicon carbide (SiC);
• a vertical drift region positioned to extend in a vertical direction inside the semiconductor layer and having a first conductive type;
• well regions positioned at two lateral sides of the vertical drift region to make contact with the vertical drift region in the semiconductor layer and having a second conductive type opposite to the first conductive type;
• a plurality of recess gate electrodes extending from a surface of the semiconductor layer into the semiconductor layer and buried in the vertical drift region and the well regions to cross the vertical drift region and the well regions in a first direction perpendicular to the vertical direction, wherein the plurality of recess gate electrodes has a first end and a second end opposing the first end, the first end is further from the surface of the semiconductor layer than the second end, and the first end is buried in the well region;
• a plate gate electrode positioned over the semiconductor layer, the plate gate electrode connecting the plurality of recess gate electrodes to each other, and the plate gate electrode having a width that is wider than a width of the vertical drift region;
• a plurality of source regions positioned in the well regions between the plurality of recess gate electrodes and having the first conductive type;
• and
• a plurality of insulating-layer protective regions positioned at least under the plurality of recess gate electrodes, respectively, in the vertical drift region, and having the second conductive type.